Technical Field of the Invention
This invention relates to sport utility vehicles, most specifically to a roof rail system that provides for multiple configurations of roof panels and mounting of accessories.
Background Art
Sport utility vehicles are defined by their ability to transport both people and cargo over a variety of terrains and under varied driving conditions. To enhance their usefulness, some sport utility vehicles are supplied with a convertible roof. Partial or complete removal of the vehicle's roof provides the occupants with a feeling of openness while traveling and enables the occupants to increase their enjoyment of the outdoor environment. Further, complete removal of the vehicle's roof and even its doors is often desirable to improve the driver's visibility of surrounding obstacles. This is particularly advantageous when such vehicles are used in rugged off-road environments where enhanced visibility of such obstacles may be essential for successful navigation. Sometimes it is desirable to remove the vehicle's roof simply to increase the available cargo space inside the vehicle.
Most of these convertible sport utility vehicles are used under changing operating conditions. Thus, where a removable roof may be desirable for recreational driving conditions, it may be necessary to reconfigure the roof for other use conditions encountered in the same excursion, including inclement weather or urban driving where noise reduction or security of the vehicle's contents is important. In addition, certain off-road vehicle configurations may not satisfy on-road regulatory requirements, and therefore the vehicle must be reconfigured according to legal regulations prior to driving on highways.
Perhaps the best-known example of a convertible sport utility vehicle is a Jeep-type vehicle. This vehicle is often equipped with a unitary hard top that is removable to expose passenger and cargo space to the open environment. Because removal and storage of the hard top are typically time consuming and difficult, the unitary top does not provide a practical solution for reconfiguring the roof to accommodate dynamic operating conditions. To address this need, a flexible soft top and its supporting structure may be installed onto the vehicle during periods of varied vehicle use conditions (such as during the summer season or during off-road trips). This roof construction affords quicker response to changing driving or weather conditions and stows in a compressed space; however, it suffers in comparison to the hard top when considering its ability to provide a quiet and secure interior space.
Cost is another substantial disadvantage for unitary hard tops. From a vehicle producer's point of view, manufacture of unitary tops is costly and requires large expensive machinery. Relatively minor changes to vehicle geometry due to model year updates require expensive mold changes; consequently, design flexibility for improvements in styling and functionality must be weighed against the high cost of mold changes. From an owner's point of view, most often damage to a small region of the hard top cannot be repaired and requires replacement of the entire top. Furthermore, shipping of such large parts is expensive due to the bulk of the parts and the protection means required.
From the above discussion it is clear that there is a need for a roof system for sport utility vehicles that provides for flexibility in configuration, provides modularization for easy handling and storage of roof components, and reduces the cost of manufacture and shipping of roof components.
A further capability that would substantially enhance the utility of the roof system just mentioned would be the provision for mounting accessories atop the roof. To further improve the capacity of vehicles to carry cargo items, a large number of after-market racks, baskets, and other carrying devices have been made commercially available. These enable the vehicle to carry large or bulky items, even those that do not easily fit within the confines of the vehicle, such as bicycles or watercraft.
Unfortunately, most existing convertible roof designs are fundamentally incompatible with the use of roof-top cargo and accessory systems. Often the two design objectives compete for the same space in the vehicle's headroom. Further, in the case of the removable hard top just mentioned, typically the hard top's construction is not suitable for withstanding the forces applied by any substantial roof-borne cargo. Such forces include potentially large static loads from roof-carried items and the rack or basket itself, and potentially large dynamic loads from shocks, vibration, or air movement, all typically induced by the driving process. Easily collapsible soft tops, while convenient to configure, are also not suitably structurally robust to handle such loads. Hard top or soft top roofs can be strengthened by braces and other devices that ultimately transfer the roof-borne loads to the vehicle frame; still, once the top is removed, these roof-top cargo systems are also necessarily removed. A provision for mounting roof-top cargo systems independently of a reconfigurable roof top would provide substantial advantage to the vehicle operator.
The above-mentioned challenges have given rise to a variety of concepts designed to improve the configurability of a sport utility vehicle's roof and interior space. Some concepts include the use of tracks or linkages and collapsible frame members to provide for an expandable and retractable/removable covering over the rear part of the vehicle (see for example U.S. Pat. No. 6,431,634, U.S. Pat. No. 7,367,615, U.S. Pat. No. 6,588,824, U.S. Pat. No. 7,240,960 and U.S. Pat. No. 5,738,405). Such systems provide for simplicity of reconfiguration and (in some cases) in-vehicle storage of frame and roof members; however, they are limited in functionality in that they are not specifically adapted to carrying external loads such as may be applied by roof-mounted aftermarket items. Moreover, such systems are designed such that once retracted, no rear frame members remain, limiting the size and extent of any available rooftop attachment locations.
To deal with this limitation, some aftermarket rack providers have provided an external frame that is mounted to the frame of the vehicle (see U.S. Pat. No. 6,755,332). Though this type of frame may be hinged or otherwise mobilized to facilitate moving portions of the rack out of the way when reconfiguring the roof, the rack must be unloaded of its cargo in order to make practical use of this feature. In addition, the frame itself contains uprights that make access to portions of the roof more difficult. Furthermore, in order to avoid interference with hard and soft top installations, they require mounting techniques that cause irreparable alterations or other such damage to the vehicle. They also add substantial weight to the vehicle in order to provide the required load bearing capacity—in essence, they create a redundant load bearing frame built upon the vehicle's intrinsic frame. One inventor has built the capability to support a roof-mounted rack into a soft top support frame (US2014077521), in effect combining the external frame concept with a soft top frame. Unfortunately, this system has no provision for use with a hard top configuration.
One system that addresses both the desire for configurable roof top and side panels and the ability to support externally mounted accessories is given in U.S. Pat. No. 7,303,227. This roof system recognizes the utility of a provision for car-top cargo space, while allowing for retraction of a substantial portion of the vehicle roof. However, this concept requires a frame that is integral with the vehicle frame and therefore does not lend itself well to after-market installation or easy removal. A second similar concept is shown in U.S. Pat. No. 6,530,621. In this convertible track system, a roof structure is composed of several vertical and horizontal members that are fixedly attached to the lower frame of the vehicle and thereby become integral with that structure, forming the upper part of the vehicle frame structure. These members have tracks to support and retain roof members as is common in the art (see particularly patents relating to sun roof installations) but also offer the advantage of providing adequate support for externally mounted devices. This integral frame design requires implementation in a new vehicle build or necessitates irreversible vehicular modifications in order to retrofit it to an existing vehicle. Also, such a design builds in unneeded cost and complexity to the overall automobile design, since the upper frame geometry is complex throughout, whereas some of the functions of the frame could be borne by simpler or less expensive members.
In this particular case it is advantageous from both a cost and a performance point of view to separate the functional requirements of vehicle structure from those of roof panel attachment, accessory attachment, and overall aesthetics. This suggests the utility of using a non-integral roof frame to provide for roof panel and accessory attachment, allowing the roof frame and the vehicle frame to each be optimized separately for their specific functions. By way of example, the materials and cross-sectional geometry of a vehicle frame member such as a roll bar can be quite less expensive and more effective in providing rollover protection if optimized for only that function as opposed to also requiring complex and aesthetically pleasing attachment geometries.
From the foregoing discussion, it is evident that there is a need for a flexibly configurable roof frame for sport utility vehicles that also offers accommodation of auxiliary attachments such as roof racks and other accessories. This roof frame is ideally inexpensive for the consumer and can be easily retrofitted to an existing vehicle without making permanent modifications.
It is therefore an object of the present invention to provide an aesthetically-pleasing roof frame that houses roof and body panels independently from roof-mounted accessories, allowing multiple independent configurations of each. It is a further object of the invention to provide a roof frame that is optimized for accommodating loads related to the roof and associated attachments but which depends on other available structural strength within the vehicle itself to support the roof frame itself and to accommodate other vehicular loading scenarios. It is yet a further object of the invention to apply the roof frame to the vehicle using only those attachment points that are already in place to avoid the need for making permanent modifications to the vehicle. This makes the invention removable and equally applicable to new vehicles and existing vehicles that are presently owned by consumers.
Further, it is an object of the present invention to utilize simple frame elements that are modular, cost effective, and adaptable over a large number of automotive frame sizes and styles, such as may be exhibited by progressive model years of a single design or by substantially different designs, including different roof styles. Finally it is an object of the present invention to provide for adjustability of the frame to accommodate manufacturing tolerances and minor model variations and still provide for adequate attachment of roof and side panels.